Locomotive lubrication

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UNIVERSITY OF CALIFORNIA.

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Locomotive Lubrication

By
W.J. SCH LACKS

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Published by

McCORD AND COMPANY
Chicago New York

< ff , t, r.« e«€..; , Qopyright.1911
" WEX COMPANY

Chicago, 111.

PREFACE

A better understanding of railway devices by
the employe handling them, works for economy
in railway service. This book on Locomotive
Lubrication is written for the express purpose of
bringing about a better understanding of this very
important subject.

Furthermore, a device such as the Locomotive
Force Feed Lubricator, which needs practically
no attention from the engineer, reaches the highest
efficiency in economy, in that it does not lubricate
per unit of time, but in per unit of work done by
the locomotive.

226072

Locomotive Lubrication

The aim of good lubrication is the reduction of
friction to a minimum.

The object of this work is to provide motive power
men with a basis for design, supervision and regula-
tion of lubrication on locomotives, and it is hoped that
the information on this subject, based on the results
of experiments, will assist in overcoming some of the
obstacles met with in locomotive lubrication.

Friction.

Friction is the force that acts between two sub-
stances in contact, opposing their sliding one on the
other, and is caused by the irregular surfaces of the
two bodies interlocking. Under the microscope these
irregular surfaces appear interlocked somewhat as
shown in the following illustration:

The- CQefftcjent ,of friction is the ratio of the force,
required 'to ' ''slide :a <bd>dy. &16ng a liorizontal plane sur-
face to the weight of the body.

From the definition of friction it is evident that it
is a loss of power in operation of the locomotive, and
its reduction, therefore, must be considered primarily
in connection with the cost of maintenance, operation
and delays, and the safety of transportation.

Conditions Affecting Friction.

The amount of friction depends:

First — On the nature of the substances in contact;

Second — On the pressure with which these two sub-
stances are held in contact ;

Third — The speed of their moving, one on the other;

Fourth — The temperature of the substances in con-
tact ;

Fifth — The substance between the two, put there to
reduce the amount of friction.

Established Laws of Friction.

First: With substances in contact variable and
all other conditions constant there is no fixed law, the
amount of friction depending on the nature of sub-
stances in contact.

Second: With varying pressures and all other con-
ditions constant, friction increases directly with the
pressure.

Third: With speed variable and all other con-
ditions constant, the friction decreases at speeds from
10 ft. to 100 ft. per minute, but at higher speeds it is

nearly directly proportionate to the square root of
the speed.

Fourth. With varying temperature, and all other
conditions constant, the amount of friction decreases
as temperature rises until abrasion takes place.

Fifth: "With substances to reduce friction variable
and all other conditions constant, these is no fixed
law, the amount of friction depending on the nature
of substance used as lubricant.

Friction — Lubricants.

The lubricants used in locomotive practice consist
of different oils, grease, graphite and lead used sep-
arately or in combination. It has been found that
each of these has certain advantages over the others
for the lubrication of different parts of the locomotive
mechanism. The general qualifications of a good lu-
bricant are given by Mr. W. H. Bailey, in Proc. Inst.,
C. E., vol. xlv., p. 372, and are as follows :

1. Sufficient body to keep the surfaces free from
contact under maximum pressure.

2. The greatest possible fluidity consistent with
the foregoing condition.

3. The lowest possible coefficient of friction, which
in bath lubrication would be for fluid friction approxi-
mately.

4. The greatest capacity for storing and carrying
away heat.

5. A high temperature of decomposition.

6. Power to resist oxidation or the action of the
atmosphere.

7. Freedom from corrosive action on the metals
upon which based.

Lubricating material made up of any number of
elements having independent qualifications, must be a
homogeneous whole and remain so under the condi-
tions surrounding the problem.

In considering qualifications Nos. 1 and 2, the cohe-
siveness, or viscosity, of the lubricant must be sufficient
to prevent the separation of its particles, and the ad-
hesion of the lubricant must be sufficient to enable it to
cling to the bearing surfaces. A lubricant having
greater adhesion or cohesion than the above conditions
require, will increase the frictional resistance.

Considering the friction developed between two sur-
faces lubricated in one case with grease and in the other
with oil, the friction developed with grease is greater
than with oil for the following reasons :

FIRST: When the grease is cold, its cohesion is
greater than oil, and its adhesion to the bearing surfaces
is less, and consequently the coefficient of friction is
higher.

SECOND: "When the grease is in a fluid, or semi-
fluid state, its cohesion, while less than when solid, is
again greater than oil, and its adhesion to the bearing
surfaces, while greater than when solid, is again less
than oil, and consequently the coefficient of friction is *
higher; and further, additional friction has to be ex-
pended to furnish the heat required to reduce the solid
grease to a fluid state.

It is an undisputed fact that the generation of heat
by friction is an extravagant method.

An abstract of a brief historical review of lubricants,
that have been used in locomotive practice, as given in
the American Railway Master Mechanics' Proceedings,
Vol. 42, 1909, follows:

"In the early years vegetable oils (principally olive
oils) were used for machine lubrication in Europe,
and, although history is vague on this subject, it is
fair to assume that the first steam locomotives were
lubricated with oils of this kind."

" There have been times in the history of steam
lubrication when anything of a greasy nature was con-
sidered a lubricant and experimented with. In the
early era of steam locomotives in this country a rail-
way publication, under the caption, 'Pork for Journal
Boxes/ stated: Why not use it? We have asked 50
railway men within as many days if they were aware
of its success. On the H. R. R. a car was packed with
slices of fresh pork, and is today as it was a year ago.
The cost per box for pork packing, that will stand at
least a year will not exceed 30 cents. "

"A railway man who used soft soap as a lubricant
seemed, to say the least, eccentric. A standard auth-
ority, 'D. K. Clark's Railway Machinery/ published
in 1855, said: 'In proportion as the bearing surfaces
are fine, hard and polished, the more fluid may be the
lubricating material ; (thus fine oil may be used in-
stead of soap.) It is probable that concussion was
originally the inducement to use soap on railways apart

from the difficulty of preventing oil from being
wasted."

"Antedating the use of mineral oil, cotton seed and
sperm oil were extensively used, followed by a more
general use of lard oil for machine lubrication and
tallow for valves and cylinders. As early as 1854 a
firm in Philadelphia introduced what they termed a
6 lubricating grease adapted to use on all classes of
running stock on railways.' They recommended it on
account of its 'freedom from gum or glutinous sub-
stances and adaptability to all kinds of weather.'

"The mineral oils or petroleums were placed upon
the market in the years soon following and on account
of their cheapness and superiority as a lubricant their
use became general. The natural West Virginia oil,
with its notable characteristics of a low cold and a
high fire test, immediately found favor and was con-
sidered superior to sperm. The production of the West
Virginia oil was limited, and as the demand rapidly
increased the supply was soon exhausted. A manu-
facturing concern in 1869 introduced for railway serv-
ice an oil for external lubrication, combining the ex-
cellent qualities of nature's best lubricating product
with other ingredients, producing an article which
met all of the requirements of the day; an oil of low
cold and high fire test, a gravity permitting a ready,
flow, and the sustaining power for support of the ever-
increasing loads upon the bearing surfaces. This lu-
bricant has stood the test of service from the date of
its introduction and is now used on the majority of the

10

railways of this country, as well as on many of the
English and European lines."

"Prior to the introduction of mineral cylinder oil,

tallow^ was the almost universal lubricant for valves

tinl

and cylinders. In some few inst.-inccsjjjj^ oil mixed

with plumbago was used, and grease introduced
through cups with double stop cocks was tried, but
melting tallow in the old familiar tallow pot was prac-
tically the universal practice for many years. Tallow
carrying a high percentage of acid was found objec-
tionable, the acid attacking the metal, pitting and ren-
dering it porous and weakening its structure/'

"The superiority of an oil free from acids, with
greater viscosity, less liable to gum, and with a higher
fire test to meet the increases in temperature was fast
relegating tallow to other uses. In 1870 there was
placed upon the market a cylinder oil meeting all the
desired requirements, furnished from a source of sup-
ply that insured uniformity in quality and quantity
to meet all demands. This cylinder oil has stood the
test through all the gradation of temperature as steam
pressures have increased from 120 to 230 Ibs., and
higher temperatures incident to the use of superheated
steam."

Mr. Wm. J. Walsh made a statement in a paper on
"Lubrication of Railway Equipment," presented be-
fore the New England Railway Club which in part is
as follows :

"The average running temperature of freight
trains is considered to be 80 degrees, and the average
running temperature of passenger trains 125 degrees.

11

We learn from experience that the proper gravity of
oil for the lubrication of all trains should be about 30
degrees, and as a degree of gravity is lost at every ten
degrees advanced in heat, it is plain to be seen that
should we supply an oil for the lubrication of a freight
train at 80 degrees, with a gravity of 30 degrees, and
if the same lubricant is used on a fast-moving passen-
ger train at 125 degrees, the gravity of the lubricant
would be reduced about 5 degrees ; or, to explain fur-
ther, if this lubricant at 30 degrees gravity is dense
enough to carry the load at 80 degrees running tem-
perature, it would not be dense enough to carry it at
125 degrees running temperature."

The use of grease as a locomotive lubricant has been
proved by tests to result in an increase of friction over
oil. There have been reasons, however, for its use in
locomotive practice.

The successful operation of oil waste driving jour-
nals requires the cellars to be dropped every ten to
twelve days, at an actual labor cost of 35c per box, to
facilitate inspection and repacking when necessary.

The following is quoted Wit from a paper by Mr.
J. R. Alexander, General Road Foreman of Engines,
Pennsylvania R. R., read before the Railway Club of .
Pittsburg :

"The economical operation of locomotives also de-
mands careful supervision of the methods employed in
handling lubricating oils, for surprising as it may ap-
pear, there are many men who believe good lubrication
can best be obtained by quantity rather than quality.

12

The ideal condition insuring perfect lubrication on loco-
motives is to have a lubricant, the globules of which will
be sufficiently strong, and the mechanical arrangement
such that the load carried on the bearing will not force
out the film of oil, thereby permitting metallic contact. ' '

Graphite is a good lubricant, especially under high
pressure. It is not adaptable to locomotive lubrication,
but its use with water or a light oil as a carrying
medium presents possibilities of development. It gives
a low coefficient of friction with cast iron or other po-
rous materials by filling the minute irregularities in the
surfaces, thus increasing the actual bearing area.

Friction-Bearing Metals.

As has been stated above, the nature of the bearing
metals determines the amount of friction between them
when other conditions are constant. While there is no
certain relation between the molecular structure of the
bearing and friction, it is generally true that the harder
and smoother or more polished the metals, the lower is
the friction developed, due to the surfaces of the metals
having fewer irregularities to interlock or overlap each
other. With metals harder than brass for bearings,
such as cast iron, a journal is more liable to cut and
wear. Such bearings do not adjust themselves as read-
ily to irregularities of the journals, and in some cases
they are too brittle to withstand stresses.

In the June, 1905, Proceedings of the American So-
ciety of Mechanical Engineers, Melvin Price stated his

13

conclusions on this question as follows: "An alloy's
resistance performance seems to be peculiar to itself,
although there are often partial similarities. Investi-
gation showed that there was no definite law between
friction and the structure of alloys."

The desired qualities of soft and hard bearing
metals are ably discussed in a report by Prof. R. C.
Carpenter in Vol. 27 of the Society of Mechanical Engi-
neers on "Locomotive Bearings," from which we quote
the following:

Desired Qualities.

"The qualities which a bearing metal should have
in order to be satisfactory are quite varied in nature,
and in some respects somewhat contradictory. The
bearing metal should first of all be one that has con-
siderable adhesion for a lubricant and is readily wetted
by it. It should also be softer than the shaft which it
supports, so that in case of lack of lubrication, or in
case hard gritty materials get in the bearing, the bear-
ing material would be injured rather than the journal.
It should be hard enough, however, to retain its shape
under any conditions of pressure or temperature which
are likely to be imposed upon it by actual use. The
melting temperature of the bearing metal should be
less than that of the journal which it supports, but
should not at the same time be readily melted by
changes in temperature which occur in practice. The
bearing metal when melted should not possess the
property of adhering or welding fast to the journal."

14

Soft Metals.

"For many purposes where the pressures are low
and temperature not likely to get high, a very soft
bearing metal, such, for instance, as may be made
from 85 per cent lead and 15 per cent antimony, is
excellent. This metal is, however, entirely unsuited
for hard service, as it readily changes its form with
increases of temperature. The bearing metal known
as genuine babbitt, consisting of tin 85 to 89 per cent,
copper 2 to 5 per cent, and antimony 7 to 10 per cent,
is probably adapted to a wider range of use than
any other metal which has ever been designed or in-
vented. On account of the large amount of tin, this
metal is expensive, and there is a great temptation to
palm off as a substitute a metal containing a consider-
able portion of lead. As a result of my experience, a
considerable amount of lead can be used, provided it
alloys perfectly with the other metals and does not ren-
der the compound too soft. Lead is, however, a poor
conductor of heat ; for a given condition of lubrication
and work performed, a bearing metal containing much
lead is likely to run warmer than one containing other
metals."

"The soft metals mentioned above possess the ad-
vantage that they can be easily melted and cast into
shape in place as desired or as needed for use on the
journal."

Hard Metals.

"There are a number of other metals which have
a high melting point and quite a large coefficient of

15

contraction which, if used for bearing metals, must
be cast in separate moulds and finished on machine
tools before applying. These metals vary in hardness
to a considerable extent, the phosphor bronze being
probably the hardest and the yellow brasses the soft-
est. I made extensive experiments with a bearing
metal of this class consisting of an alloy of aluminum,
zinc and copper, the zinc being largely in excess of
the other ingredients. That alloy was very satisfac-
tory when zinc of the proper purity could be obtained,
but was so much affected by the impurities likely to
be found in zinc that it was frequently quite unsatis-
factory in practice.''

"I have found that a mixture consisting of 50 per
cent of aluminum, 25 per cent of zinc and 25 per cent
of tin forms an alloy which has many excellent prop-
erties as a bearing metal. It is light in weight, has
a fair degree of hardness, a moderately high melting
point, and, so far as I can determine from laboratory
experiments and some practical applications, is a su-
perior metal for certain kinds of bearings."

Conclusion.

"From the uncertain nature of our methods of
testing and from the varied conditions under which
bearing metals are used, it is easy to understand the
differences of opinion which are held by various en-
gineers regarding the quality of the same bearing ma-
terial. This fact also probably explains the reasons
why such a variety of prices and grades of bearing
metal can be marketed."

16

"In my opinion there is no possible criterion, no
single definition or specification, which can adequately
describe a bearing metal which shall be universally
satisfactory for all work and conditions. ' '

Different Brass and Babbitt Mixtures.

Very good results are obtained with brass bearings
of the following composition :

Copper not less than 79%

Lead not less than 9

Total softening elements 88%

Tin not to exceed 10%

Zinc not to exceed 2%

Total hardening elements 12%

100%

A good babbitt metal for lining car journal brasses
is: Lead ......................... 78%

Antimony

Tin ......... ................ 3%

100%

A good metal for piston rod and valve stem pack-

is: Lead ........................ 86%

Antimony .................... 12%

Tin ......................... 2%

100%

17

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18

Lubrication — Driving Journals.

Tests have been made proving that driving journal
friction increases' proportionately as the distance trav-
eled after oiling.

The lubrication of driving journals with oil by
cups and cellars caused so much trouble in locomotive
operation, due to the increase in length of runs, periph-
eral speeds and bearing pressures combined with the
lack of a regular feed of the lubricant, that grease was
resorted to by some railroads because it afforded a
positive feed, which materially reduced the annoyances
and expense of hot driving journals.

When the first experiments were made with grease
it was found that the grease cellars, with the usual
oil-hole left in the top of box and with the brasses fit-
ting the journal as snugly as was the practice with
oil, would not give satisfactory results. In these ex-
periments it was found that the grease was forced out
through the hole in the top of the box. In a number
of instances wooden plugs were driven in the holes to
prevent this, but the pressure exerted by the revolving
journal forced these plugs out, demonstrating the mag-
nitude of the pressure thus generated. One explanation
, of this pressure is that the revolving journal in generat-
ing pressure acts like a paddle-fan water wheel re-
versed in that the minute irregularities on the surface
of the journal fill with the lubricant and carry it to
the pressure side of the brass where it adds to the
amount previously taken up and retained ; a kind of
cumulative pressure which continues until the pressure

19

has reached a point that will not permit more grease
entering between the journal and the bearing.

After these grease difficulties were overcome, the
loss of tractive force, with the consequent higher cost
of operation per ton mile hastened the perfection of
the automatic oil force feed lubricator for journal
lubrication.

The following is another quotation from Mr. J. R.
Alexander's paper:

"Driving box lubrication is obtained by means of a
supply of oil from both top and bottom of the journal,
while tender and car journals depend altogether on the
supply of lubricant from the under side. In either case,
however, it is essential that the packing in journal box
cellars be maintained in good condition, and to this
end it is necessary that a good quality of wool waste, or
other suitable material, be provided and same prepared
for use by being submerged in oil for not less than 48
hours, after which the waste should be drained of free
oil in excess of 4 Ib. oil per pound of waste, and fur-
nished to inspectors well loosened up and not wrapped
up tightly in balls. In packing journal boxes it is a
great mistake to have the waste contain too much free
cil, as this makes it impossible to pack sufficiently tight
under the journal to prevent pounding down after loco->
motive or car is in motion. Dust guards at back of
journal boxes should be maintained in good condition
and the packing kept firmly set up to the journal at the '
rear of the box. At the sides the waste should not be
allowed to extend above the center line of the journal,
for if the waste is allowed to pack against the rising side

20

of the bearing it will soon become glazed and act as a
wiper, and is very likely to clean the journal free of oil,
preventing it from passing under the bearing. The
best results and with considerable economy in the amount
of oil and waste, will be obtained by having locomotive
and tender journal box cellars not more than 2^ in.
deep, as experience proves that capillary attraction will
not bring sufficient oil through waste from a greater
depth/7

In reference to the above it might be stated that aver-
age wool waste under most favorable conditions seldom
absorbs over 3 Ib. oil to 1 Ib. waste.

Lubrication — Valves and Cylinders.

The question of internal lubrication has been given
additional consideration in recent years, due to in-
creasing difficulties met with in high steam pressures,
and superheated steam with irregular lubrication.

The lubrication of valves and cylinders to be effect-
ive must be regular and in proportion to speed and
cut-off, because one of the fundamental laws of fric-
tion is, as previously stated, that it |^M3£e& directly
as the speed of the moving parts up to 100 ft. per
minute and increases nearly directly proportionate
to its square root at greater speeds. This applies to
valve and cylinder as well as journal lubrication.
Valve and cylinder lubrication should be proportionate
to the cut-off at which the locomotive is working be-
cause at the longer cut-off the valve travel is greater,
and while piston travel is the same the mean effective

21

pressure and consequently the temperature in the cyl-
inder is greater, both of which conditions require more
lubricant. In addition to this there is the increased
tendency to work water at the longer cut-off when
starting.

Driving journal lubrication should be proportionate
to the cut-off for the reason that at longer cut-offs the
mean effective pressure in the cylinder is increased,
thereby increasing the pressure on the working sides of
the journal bearing.

Relative to the amount of lubricant necessary the
Committee on Locomotive Lubrication of the Ameri-
can Railway Master Mechanic's Association in 1907
made the following recommendation :

' 'Your committee feels that for internal lubrication
70 miles per pint for large freight locomotives and 80
miles per pint for large passenger locomotives seems
to be the amount needed to lubricate properly. The
amount to each class depends upon the speed at which
the locomotive is running; in bad water districts
the oil allowance should be increased about 25 per
cent."

Lubrication — Superheated Steam.

Oil must be fed regularly to overcome the difficulty
of lubricating valves and cylinders, in the case of sup-
erheated steam, beause of the loss of lubrication due
to the dryness and high temperature of the steam it-
self. The fact was emphasized in the 1907 Proceed-
ings of the Traveling Engineers' Association, and au-

22

tomatic force feed lubrication was recommended. The
fastest superheated locomotive in the world is lubri-
cated by an automatic force feed system.

Lubrication — Regular or Irregular.

Irregular lubrication necessitates using an exces-
sive amount of oil, causes unnecessary friction which
results in most of the hot bearings and cut surfaces,
and in the case of valves and cylinders materially
affects the proper distribution of steam by overburden-
ing the valve gear.

These conditions increase the cost of operation by
increasing coal consumption and by decreasing the
available power of the locomotive. The overtaxing of
the valve gear also causes more rapid wear of pins and
connections and earlier repairs.

Methods of Lubrication— Hand Oiling — Oil Cups.

At the outset the moisture of low pressure steam
was depended upon to lubricate valves and cylinders,
but soon oil cups were placed on steam chests,
and were filled whenever stops were made. The next
step was to place the oil cup in the cab of the loco-
motive, so that it could be operated by the enginemen.
This method of lubrication was nothing more than
hand oiling, but it was more convenient.

Methods of Lubrication— Sight Feed, Hydrostatic.

The second step in valve and cylinder lubrication,
taken about twenty-five years ago, was the introduction
of the hydrostatic sight feed lubricator. The principle

23

upon which it operates is, that a column of water under
boiler pressure forces the oil floating on top of it into
cylinder oil pipes leading to the bearing surfaces. The
difference in pressure which forces the oil is equivalent
to the weight of a column of water equal in height to
the difference in levels of lubricator outlet and bottom
of choke plug, less the friction in the pipe, plus the
difference between boiler and steam chest pressure.

Method of Lubrication — Force Feed.

Force feed lubricators were perfected first for sta-
tionary engines and automobiles, and about five years
ago the lubricator with automatic features was finally
designed for locomotive service. The European rail-
ways have used force feed lubrication much longer,
but the mechanical construction of the lubricator did
not appeal to American engineers, especially on ac-
count of the increased consumption of oil due to the
impossibility of fine adjustment of feed.

With the modern American system of automatic force
feed lubrication, motion is obtained from some part of
the valve mechanism, the motion of which is propor-
tional to that of the valve itself, and is transmitted
through a mechanical transformer to the lubricator
proper, located in the most convenient place on the
locomotive. Individual pumps force the oil through
individual pipes to the bearings to be lubricated. The
lubricator operates automatically only when the engine
is running, and the speed of the plungers in the lubri-
cator is entirely dependent upon the travel of the
valve.

24

Before starting the locomotive, after standing some
time, the engineman operates the plungers several times
by the hand crank to oil each bearing before moving
engine. As the pumps are capable of developing over
3,000 Ibs. pressure, the lubrication is absolutely posi-
tive, the oil being forced direct to the bearing surfaces.
There is no pressure in the reservoir, which is an assur-
ance against accidents, and permits the filling of
the reservoir while the lubricator is in operation. The
amount of oil delivered to any bearing surface is de-
pendent upon the stroke of the individual pumps of
the lubricator and the feed may be adjusted from one
drop in 10 strokes to 20 drops in one stroke by chang-
ing the stroke of the plungers. The feeds to the dif-
ferent bearings are independent of one another and are
regulated to suit the conditions. Adjustment once
made, is maintained by locking the adjusting nut.

The force feed lubricator is regulated on trial of
each locomotive. The mileage per pint of valve oil
will vary from 70 to 150, depending on type, power
and speed of locomotive, steam pressure and tempera-
ture, grade of track, etc.

Direct and regular lubrication effects a saving in oil,
an increase in engine efficiency and a decrease in the
wear of the parts lubricated.

The McCord force feed lubricator does not lubricate
per unit of time, but in per unit of work performed,
which is not only in direct proportion to the speed, but

25

also in proportion to the cut-off at which the engine is
being worked. It is automatically regulated by the
speed of the engine and the position of the reverse
lever.

Power and Tractive Force-Lubricants.

A good lubricant applied in regular sufficient quanti-
ties reduces the internal friction of a locomotive there
by increasing the effective tractive force and horse-
power. The tests made by the Pennsylvania Railroad
at the Louisiana Purchase Exposition demonstrated
that the use of grease instead of oil on driving jour-
nals, increased the friction per journal by from 75 per
cent to over 100 per cent, depending on the peripheral
speed.

The report of Prof. W. F. M. Goss, printed in the
1906 proceedings of the American Eailway Master
Mechanic 's Association, is here quoted in part :

"Accepting the oil lubrication as a basis of compari-
son it appears that at 20 miles an hour the loss of power
resulting from the use of grease is slight, so small in
fact as to be almost negligible, but as the speed is
increased the loss is increased and at 60 miles per hour
it amounts to from 140 to 160 horsepower. The equiv-
alent coal loss, assuming four pounds of coal per horse-
power hour, is something more than 500 pounds per
hour. A summary of results in form permitting easy
comparisons is set forth in the accompanying table."

Speed of Engine 20 Miles an Hour.

1. Pounds pull of the draw-bar necessary to over-

come friction of the engine.

Cold start Grease 1,578 Oil 1,435

Hot start Grease 2,222 Oil 1,549

Average 1,900 1,492

2. Tractive force lost by use of grease 408

3. Horsepower lost 21.8

4. Coal lost per hour run (assuming 4 pounds per

horsepower hour) 87.2

50 Miles an Hour.

1. Pounds pull at the draw-bar necessary to over-

come friction of the engine.

Cold start Grease 1,862 Oil 555

Hot start Grease 1,628 Oil 780

Average 1,745 667

2. Tractive force lost by use of grease 1,078

3. Horsepower lost 143.7

4. Coal lost per hour run (assuming 4 pounds per

horsepower hour) 574.8

60 Miles an Hour.

1. Pounds pull at the draw-bar necessary to over-
come friction of the engine.

Cold start Grease 1,727 Oil 655

Hot start Grease 1,804 Oil 873

Average 1,765 764

27

2. Tractive force lost by use of grease 1,001

3. Horsepower lost 160.2

4. Coal lost per hour run (assuming 4 pounds per

horsepower hour) 640.8

These tests were made on an Atlantic type locomo-
tive with grease and oil used in each case on driving
journals and crank pins.

We are informed that oil was fed to driving journals
by gravity through holes in the top of the driving
boxes. These holes released whatever pressure the
revolving journal generated ; thus relying for lubrica-
tion on the little amount of oil that, due to its adhesive
quality, could not be forced out from between the jour-
nal and the bearing.

The modern automatic force feed method forces the
oil into the top of the driving box against the pressure
generated by the revolving journal and raises the box
from the journal as far as the oil packing on the ends
of the driving box will allow, thus separating the jour-
nal and the bearing with a thick film of oil. This fills
all irregularities in the bearing surfaces, so that the
actual bearing surface more closely approximates th(
projected areas. It separates the journal and bearing
sufficiently to clear projections on one or the other that
would ordinarily cause cutting. There are actual cases
of cut journals thus lubricated, running as cool as the
smooth journals on the same engine.

In experimenting with a driving box in the labora-
tory it was found that a gauge piped to the cavity in
the top of the brass recorded a pressure as high as four

28

times the bearing pressure per square inch that the
weight on the bearing divided by the projected area
should have given, which proves that the actual
pressure per square inch is a very different quantity
from that figured from the projected area. The in-
creasing of the realized area by intervening a thick film
of oil between the bearing and journal will overcome
troubles due to overloaded journals.

With the modern automatic force-feed method of
lubrication, the oil, in being forced through the top of
the box, is ready to go to the service or pressure side
of the journal whether the engine is backing or going
ahead, and does not have to ride up the other side first
and be scraped off by the brass before it has reached
the surface that most needs the lubricant.

For this reason driving box brasses may be fitted up
without side clearance and a tight fitting cellar may be
used to prevent any "pinching" of the journal. This
method gives the brass more crown bearing and allows
that much more side-wear before the journal is as loose
in the brass as when driving boxes are fitted for grease
lubrication from the under side.

Excessive side clearance or pound between driving
journals and brass subjects locomotive machinery and
frames to severe dynamic stresses and this clearance
together with any looseness in the rods, requires the
piston to move a certain distance in taking up lost
motion before moving the engine. The volume of steam
used in this piston displacement is a dead loss and in
the case of a modern 22-inch consolidation engine with

29

i/i-inch total play in the boxes and y8-inch on each
crank pin, it amounts to about 225 Ibs. of coal per hour.
All moving parts in a reciprocating engine should
be as devoid of lost motion as possible, for as soon as
there is lost motion, the stress to be resisted by the
pistons, rods, crank-pins, driving axles and frames, is
changed from a static to a dynamic stress, whose mag-
nitude and effects (as was learned from draft gear
experiments) are extremely difficult to determine.

A lubricator does not operate perfectly if it fails to
feed automatically in accordance with requirements of
the service, which is in proportion to speed and cut-off.
The automatic lubricator relieves the engineman of the
necessity of the care of it and allows him that time for

other duties. „ , .

Conclusions.

One of the chief aims in modern transportation is
a safe reduction in ton mile costs. A very important
item entering into this is locomotive efficiency, which
depends on a number of conditions, one of which is the
reduction of friction. This is accomplished by using
the best lubricant with the best method of applying it.

The automatic force feed system of lubrication does
not reduce the amount of oil actually needed but
does reduce the waste of oil which accompanies other
methods. While the automatic force feed system re-
duces this waste, the principal benefit derived is a
more nearly constant coefficient of friction in the bear-
ings lubricated. This is lower than the average of
the varying coefficients of friction with any other
method.

30

Advantages Derived by the Use of McCord System of
Force Feed Locomotive Lubrication.

1. Lubrication is positive.

2. Lubrication is proportional to valve travel and
therefore proportional to the work done by the loco-
motive.

3. When locomotive stops, lubrication stops.

4. Lubricator pumps against a pressure of more
than 3,000 pounds.

5. No pressure in reservoir insures against leakage
and accidents to enginemen.

6. Reservoirs can be filled while in full operation.

7. Each feed can be adjusted separately.

8. Feed is adjustable from one drop in 10 strokes
to 20 drops in one stroke.

9. Adjustment of feeds once made, they remain
accurate and adequate under all conditions.

10. All moving parts are immersed in oil.

11. Oil consumption is reduced and engine efficiency

is increased.

31

Directions for Operating the McCord Force Feed
Lubricator.

1. There is no pressure in this lubricator, conse-
quently no steam to be turned off or no draining to
be done before filling.

2. To fill, remove the filling cap and pour in the
oil after it has been heated sufficiently to pour freely
through the strainer at the filling hole. This may be
done either when the engine is standing or running.

3. Do not fill this lubricator with oil drained from
a hydrostatic lubricator, as it will contain water.

4. Do not allow oil to feed out below gauge line.

5. The feed is increased by screwing down the
knurled nuts on the top of the pump plungers, and is
decreased by screwing them up.

6. The lubricator body should be kept warm to the
touch so that the oil will remain thin enough that the
pumps may handle it easily. A heater chamber is pro-
vided on the bottom of each lubricator into which a
small amount of steam can be admitted in cold weather.

7. This lubricator operates automatically when the
engine is in motion, so there is nothing to turn on at
the beginning of a run or to turn off at the end of
a run.

8. Should it be necessary to give the engine more
oil than is obtained by the automatic mechanism, op-
erate the hand crank on end of lubricator.

32

Directions for Operating and Testing the McCord Locomotive
Force Feed Lubricators.

To Put the Lubricator in Service.

Remove the filling cap and fill the lubricator with
warm oil; disconnect below all the terminal check
valves and operate the hand crank until oil appears at
the bottom of each check valve. Then connect up each
terminal check valve and driving mechanism and the
lubricator will be ready for operation.

To Test Out the Lubricator Should Any Trouble
Be Reported.

Disconnect the operating mechanism at the valve
stem, operate the ratchet arm slowly by hand, and see
that the lubricator shaft revolves with each return
movement of the ratchet arm.

Disconnect all oil pipes at check valve joints. The
oil pipes should be full of oil. If any pipe is found
empty or only partially full of oil, it is an indication
that there is something wrong with the check valve
or pump on this oil line, or that the oil pipe leaks or is
stopped up.

Admit steam under the check valve. No steam
should blow out at the oil port connection. If there
should be a leak here, remove the check valve and
grind in the needle valve seat. Use powdered glass or
any grinding compound same as used on air brake
work, but be sure that this grinding is done when the

33

valve is hot, as it is under this condition that the valve
should be tight. Be sure to clean the check valve and
seat thoroughly after grinding so that no small parti-
cles can get under the valve seat and cause leak.

oteam
If the check valve is flBHH tight, disconnect the oil

pipe connection at the lubricator pump and turn the
hand crank ; if oil shows at the pump discharge, the
pump is 0. K. If the pump does not work, take it out
and make sure that the packing around the pump
plunger is tight, that there is no waste or other ma-
terial collected around the pump suction pipes, and
that all the ball checks in the pump are in their proper
places.

Pump kerosene through the pump to wash and clean
the ball checks and seats. The plunger packing should
be elastic enough that it will not be necessary to screw
the packing nuts down so tight as to bind unnecessar-
ily on the plungers.

To determine if the oil pipe leaks, connect a pressure
gauge on to the end of the oil pipe and operate the
lubricator by hand. The pipe line should hold a pres-
sure of at least 300 Ibs. without any variation on the
gauge. This is also an absolute test that the ball checks
and the packing in the pump are tight. If there is an
obstruction in the oil pipe, no oil will appear at the
end of the pipe after the lubricator has been operated
by hand a reasonable length of time, and further, the
lubricator shaft will turn hard on the down stroke of
the plunger, and oil will leak out at the packing nut,
and at the pump outlet connection.

34

After doing work on any or all of the oil pipes,
screw all union joints tight and turn hand crank until
the oil pipes are full of oil before the engine goes out.
This is important. The slightest leak in the whole sys-
tem should be avoided, for it will materially affect the
regular delivery of oil.

The feed is adjusted by means of the knurled nuts
on the top of the pump plunger. Screw these nuts
down to increase the feed and screw them up to de-
crease the feed.

McCORD AND COMPANY

Peoples Gas Bldg. 50 Church Street

Chicago. New York.

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